LoongArch: Replace seq_printf() with seq_puts() for simple strings

LoongArch: Replace seq_printf() with seq_puts() for simple strings

Fix warnings like: "Prefer seq_puts to seq_printf" by checkpatch.pl.

Replace seq_printf() calls with seq_puts() in show_cpuinfo() when
outputting simple constant strings without format specifiers.

This improves performance slightly as seq_puts() avoids parsing the
format string.

Signed-off-by: George Guo <guodongtai@kylinos.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>